1. Field of the invention
Exemplary embodiments of the present disclosure relate to a signal coupling apparatus for power line communication.
2. Description of Related Art
Generally, a PLC (Power Line Communication) is a method based on a communication signal superimposed on a carrier wave transmitted via a high voltage distribution line or a low voltage distribution line installed outdoors or indoors, to thereby transmit a voice signal and/or a data signal at a high speed.
A power line, as a network installed to supply electricity to homes and offices, has been to the fore as the most ideal subscriber network in terms of wide (90% or more) distribution rate and excellent maintainability and repairability, albeit being inadequate as a communication network due to complicated construction and poor line characteristics.
Particularly, the power lines can save huge investment costs in view of the fact that no new communication networks for communication are needed as existing electric outlets or receptacles installed at each place can be used as communication terminals. In other words, existing power lines that already have been run to many homes and offices can be used to carry data signals to and from the homes and offices. The PLC is configured such that a PLC signal (9 kHz to 30 MHz) is transmitted on a commercial AC (50 Hz or 60 Hz) flowing on a power line, and the transmitted signal is separated by a frequency filter for use at a reception side.
FIG. 1 is an exemplary schematic view illustrating a remote meter-reading system mounted with a repeater embedded with a PLC modem.
A wattmeter (10, 20, 30) at each consumer may be installed with a PLC, and a concentrator (50) performs a power line communication with each consumer (10, 20, 30) via a power line (L). The concentrator (50) receives tele-metering information from each consumer (10, 20, 30) and provides the information to a power provider server via a data communication network. In the remote meter-reading system thus described, a repeater (40) may be installed on an electric pole if necessary, where an interface device is required for coupling a signal on the power line (L) to the repeater.
A conventional interface device for coupling the power line signal is generally configured by a copper wire inside a power line coating being electrically connected to a predetermined screw pin. The conventional interface device suffers from disadvantages in that work efficiency deteriorates according to a worker, a power line can be damaged by a force applied by a worker for turning a screw pin and work risk increases because a high voltage power line are directly connected to the screw pin. Another disadvantage is that moisture and foreign objects may be introduced into the coating of the power line through the screw pin to decrease the communication performance.